Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
  • A23C19/00—Cheese; Cheese preparations; Making thereof
  • A23C19/02—Making cheese curd
  • A23C19/028—Making cheese curd without substantial whey separation from coagulated milk
  • A23C19/0285—Making cheese curd without substantial whey separation from coagulated milk by dialysis or ultrafiltration

Definitions

• the present invention relates to a process for the prepara- tion of cheese on the basis of milk or milk products where after pasteurizing and partially cooling the material, said material is subjected to membrane filtration, further cooling, dosing of rennet and starter and optionally other additives, mixing and casting, again followed by after— treatment and curing, as well as an apparatus to be used when carrying out the process'.
• the invention relates to an improved process of preparing so-called "cast” cheese, where milk or a milk product is firstly concentrated by membrane filtration, whereupon the actual cheese making process is carried out by adding rennet and starter.
• GB patent specification no. 2.101.866 (Rubin et al. ) dis ⁇ closes a process for preparing a so—called cheese—base by ultrafiltration combined with diafiltration (DF) of milk followed by evaporation.
• the retentate is inoculated with a starter prior to and subsequent to evaporation.
• the process is used to prepare a raw material suitable for the preparation of processed cheese.
• the process is unsuitable for the preparation of classical , semi-hard cheese.
• US patent speci ication no . 4.355.048 dis- closes the preparation of semi—hard cheese, such as Gouda and Edam, by ultrafiltering skimmed milk to obtain a reten ⁇ tate having a dry matter content of at least 31.5%, such as in the range of from 31.7 to 32.4%.
• the retentate is then mixed with fat, such a milk fat, and rennet and starter are added, whereupon the resulting material is cast, pressed, salted and cured in a conventional manner.
• a dry matter content of 38% by weight for a 20+ cheese and of 48% by weight for a 50+ cheese is obtained due to the addtion of fat.
• the high dry matter contents are thus obtained by subsequent addition of fat and, a retentate having the final dry matter content is thus not prepared by ultrafil- tration. Also here, two highly viscous production lines are involved. Furthermore, no heat treatment of the retentate is carried out.
• the invention thus relates to a process and an apparatus for the preparation of cheese on the basis of milk or milk products where after pasteurizing and partially cooling the material, said material is subjected to membrane filtration, further cooling, dosing of rennet and starter and optionally other additives, mixing and casting followed by after—treatment and curing, said process being charac ⁇ terised in that membrane filtration is carried out to obtain a retentate with a dry matter content of x % by weight, where x is between 38 + 1/3 (y - 20) and 44 + 1/3 (y -20) and where y is the fat content in % by weight calculated in relation to the dry matter content, that the retentate is subjected to heat treatment at 64-70°C for 10-40 seconds, that the material is cooled to a temperature not higher than 40°C before dosing the rennet and the starter and optionally other additives and that the process is carried out under such conditions as to time and the shear force that the viscosity of the material is not more than 60,000
• the present invention is surprising in that the problems connected with working with a high dry matter content and heat treatment of the retentate, are avoided.
• a particular problem now avoided is the uncontrollable increase in viscosity of the retentate in the course of the process from membrane filtration to dosing of rennet and starter culture. Particularly when left to stand, protein-rich retentates develop a structure such that the viscosity increases. This is avoided by carrying out the process under such conditions as to time and shear force that at the start of the dosing the viscosity of the material is not more than 60,000 cP measured at a shear rate of D — 12 sec "1 and 35 °C.
• the present invention is further ad ⁇ vantageous in that it is no longer necessary to maintain a temperature of above 40°C during the addition (dosing) of rennet and starter and the subsequent mixing.
• thermophilic starter cultures It is possible to use conventional starter cultures like the ones used in the preparation of classical, semi—hard cheese. This is one of the prerequisites for the finished cheese having the good consistency and taste valued by consumers.
• the process from the end of the membrane filtration to the dosing may advantageously be carried out under conditions where the material is in constant movement.
• the invention also relates to an apparatus to be used when carrying out the process according to the invention, said apparatus comprising units for preceding pasteurization and partial cooling and units for subsequent after-treat ⁇ ment and curing.
• the apparatus is characterised in that it comprises
• the retentate feeding pump may advantageously be a positive pump functioning as a regulating means to regulate the dry matter content of the retentate.
• the unit ad ⁇ vantageously comprises a scraped surface heat exchanger system.
• the dosing means is advantageously formed in such a manner that it comprises a pipeline for retentate flow and an Inlet opening for a dosing flow of starter and rennet, which opens up substantially in the middle of the retentate flow.
• the inlet opening is formed to allow inlet of the dosing flow in the same direction as (downstream) the retentate flow. In practice, such design has been found to provide the best homogenous mixture between the two flows .
• the mixing means is a static or dynamic mixing means.
• the process according to the Invention it is possible to work with a retentate having a considerably higher dry matter content than the ultrafiltration retentates pre ⁇ viously used.
• the practical limits to the dry matter content depend on the fat content, as a higher fat content in the dry matter makes it possible to keep a higher total dry matter content.
• the lower limit for the dry matter content is conventionally dictated by the desire to obtain a suitable hardness, for instance allowing the cheese to be sliced.
• the upper limit is dictated by practical con ⁇ siderations, as an excessively high dry matter content may mean a risk of viscosity problems and thereby problems ensuring a reasonable ultrafiltration capacity, a suf ⁇ ficient heat treatment and a homogenous admixture of rennet and starter .
• the lower limit for the dry matter content of the retentate is 38%, preferably 39%, such as 40%.
• the upper limit is around 44% by weight, preferably 42% by weight, such as 41% by weight.
• the dry matter content should be at least 41.3% by weight, preferably at least 42% by weight, such as at least 43% by weight and not more than 47.3% by weight, preferably not more than 46% by weight, such as not more than 44% by weight.
• the dry matter content should be at least 46.3% by weight, preferably at least 47% by weight, such as at least 48% by weight and not more than 52.3% by weight, preferably not more than 50% by weight, such as not more than 49% by weight.
• the dry matter content for a 50+ cheese should be at least 48% by weight, preferably at least 49% by weight, such as at least 50% by weight, and not more than 54% by weight, preferably not more than 52% by weight, such as not more than 51% by weight.
• the dry matter content of the retentate obtained by the membrane filtration may advantageously be regulated by using a positive pump as retentate feeding pump.
• the power necessary to maintain the desired flow in the individual recirculation loops of the ultrafiltration apparatus is directly dependent on the dry matter content.
• the measuring signal for the power in kW from the pump(s) in the last loop(s) may thus be used as regulation signal to regulate the speed of the feeding pump to the heat treatment and cooling unit.
• the process from the end of the membran filtration to the casting takes place within a relatively short period of time, so that a too high viscosity Is not bulit up. It will thus be an advantage to work continuously and not to use buffer containers during this part of the process. If, after all, it is necessary to use a detention or "stand—by" period, it is important that the retentate is kept in motion, the retentate having a thixotropic nature. Of course, the thixotropic viscosity structure may be destroy ⁇ ed by means of shear force, whereby the retentate get the desired low viscosity immediately before the dosing of rennet and starter. As, strictly theoretically, it is thus not absolutely necessary to carry out the process from the end of the membrane filtration and to immediately before the dosing of rennet and starter continuously, it must be understood that it is of course most practical also to carry out this part of the process continuously.
• the retentate is subjected to a heat treatment and subsequent cooling immediately before the dosing of rennet and starter.
• a heat treatment and subsequent cooling immediately before the dosing of rennet and starter.
• the heat treatment is carried out as late as possible during the process reduces the risk of unwanted growth of bacteria.
• the heat treatment is carried out by heating to 64—70°C, such as around 69 ⁇ C for 10-40 seconds, such as 20 seconds .
• the heat treatment is conventionally carried out in a scraped surface heat exchanger system, where the heat exchanger system is used both for heating and for the subsequent cooling of the material to a renneting temperature of not more than 40°C.
• the viscosity measurements are carried out using Rheomat 30 , Contraves .
• the casting may be carried out with two or more pouring stubs, thereby avoiding stopping the flow.
• Examples of usable starter cultures to be used when carrying out the process according to the invention include mesophilic acidifiers, e.g. the BD culture B-ll mixed with the 0 culture R—603. These starter cultures are available from Chr . Hansens Laboratorium, H ⁇ rsholm, Denmark. Dif ⁇ ferent mesophilic aroma cultures may advantageously be used together with the starter culture.
• Rennetability designates the number of litres of milk which 1 litre of rennet is able to coagulate in 40 minutes at 35 °C .
• the subsequent mixing means may be a conventional dynamic mixing means, i.e. in the form of e.g. a set of propeller stirrers introduced into the flow.
• a so—called static mixing means i.e. a piece of tube with baffle plates forcing the flow to deflect sufficiently for the flow to be thoroughly mixed.
• the process according to the invention may be carried out using milk or milk products with a pH value of between 6.3 and 6.8, however preferably between pH 6.5 and 6.7.
• a pH value of between 6.3 and 6.8, however preferably between pH 6.5 and 6.7.
• problems of protein gelation may arise in connection with heat treat ⁇ ment of the retentate at pH values below 6.5, as such retentates has a relatively high protein content.
• Raw milk or one or more fractions of raw milk including reconstituted dry milk is used as starting material.
• the starting material is firstly standardized to ensure that the starting material is uniform and has the desired fat content dependent on the type of cheese desired.
• cream is usually separated during standardization.
• the standardized milk is pas ⁇ teurized in a conventional manner by heating to 70—75 °C, preferably 72°C for a period, ususally approx. 15 seconds, adequate to ensure sufficient germ reduction.
• the pas ⁇ teurized mixture is cooled to below 10°C, usually about 6°C if the pasteurized milk is to be stored.
• the milk is reheated to a temperature of approx. 45-55°C, preferably 50 C C, whereupon it is subjected to membrane filtration. It is also possible to cool to the membrane filtration temperature after the pasteurization and to carry out membrane filtration without intervening storage.
• Membrane filtration is carried out by continuous ultrafil- tration (UF) with diafiltration (DF) to obtain a retentate having a dry matter content substantially corresponding to the desired dry matter content of the finished cheese.
• the amount of lactose is reduced by diafiltratio , said amount being adjusted to a predetermined value which ensures that sufficient lactose is available to the starter culture during the curing and ripening of the cheese, for instance approx. 0.8-1.9% by weight of lactose.
• the optimum lactose level depends on the type of cheese desired. In case of a low fat content and thereby relatively higher protein content, a relatively high lactose level must be used.
• the lactose content for a 45+ cheese is conventional ⁇ ly around 1.1%, whereas for a 20+ cheese, the lactose content is conventionally around 1.6%.
• the retentate obtained by membrane filtration is subjected to heat treatment, where the retentate is heated to 64- 70°C, especially 65-69°C, such as about 69°C for 10-30 seconds, preferably approx. 20 seconds, whereupon it is immediately cooled to a temperature not higher than 40 D C, preferably not higher than 35°C* such as about 31°C, where ⁇ upon rennet and starter culture are still continuously and quickly admixed under vigorous agitation.
• a heat treatment of the above extent is assumed to cor ⁇ respond to low pasteurization, which is defined as a heat treatment where the alkaline phosphatase enzyme of the milk is inactivated.
• the dosing takes place in the form of a dosing flow which is introduced through an inlet opening preferably opening into the middle of the pipeline through which the retentate flow is running.
• the dosing flow is preferably introduced downstream the retentate flow, i.e. in the same direction as the retentate flow, thereby avoiding the relatively low- viscous dosing flow to be pressed against the sides of the pipeline without being sufficiently mixed into the reten ⁇ tate.
• the rennet and the starter culture are introdueced as an aqueous suspension in a volume of 1—1.5% of the volume of the retentate flow.
• the mixing means may be a static or a dynamic mixing means.
• a static mixing means may consist of a piece of tube with baffle plates, said baffle plates deflecting and thereby mixing the flow as it passes.
• Examples of dynamic mixing means include such where one or more rotating stirring means, for instance propeller stirrers, are placed in the flow.
• the viscosity of the retentate should not have increased to more than 60,000 cP when the rennet and starter culture are dosed.
• the retentate being thixotropic, it is posssible to reduce the viscosity by means of shear force.
• the material is cast, for instance by automatic filling of moulds. It is an essential feature of the process according to the invention that the process from the dosing to the casting takes place continuously and quickly as the viscosity of the material starts to increase irreversibly after the dosing.
• the process may proceed in the following manner. Following the casting, the moulds are left to stand for 3—10 hours, such as 4 hours .
• the cast, uncured cheeses are demoulded and acidi ⁇ fied and brine salted on acidificaton and brining shelves.
• the cheeses are then left to stand for at least 10 hours, whereupon they are again brine salted and left to ripe.
• the dry matter content obtainable in the finished cheese especially depends on the desired fat content and on the ripening method.
• the fat content calculated as the per ⁇ centage of fat in relation to the dry matter content, may vary from less than 10% to 50% or higher if required.
• the relevant ripening method may be surface ripening or ripening as rindless cheese.
• the production process is initiated by fat standarization of the milk in relation to the protein content of the milk, taking into account the desired fat content of the cheese and the fact that all whey proteins act as cheese proteins in the process according to the invention. This again is due to the fact that the whey proteins are retained in the membrane filtration retentate during the membrane fil— tration process.
• the standardized milk is then pasteurized at 72°C for 15 seconds like traditional cheese milk and is cooled either to the membrane filtration temperature of 50°C, if the milk is pumped directly to the membrane filtration apparatus, or to 6°C, if it is to be stored before further proces ⁇ sing.
• the pasteurized cheese milk After being preheated to 50 C C for 5 minutes, if the milk has been cooled, the pasteurized cheese milk enters the ultrafiltration apparatus to be continuously concentrated up to a dry matter content corresponding to a semi—hard fresh cheese, for instance 49% dry matter for a 45+ cheese.
• the ultrafiltration process is not only a milk fat and protein concentration process. It is also a process in which the lactose content of the ultrafiltra— tion retentate is reduced by diafiltration and standardized to a predetermined level, whereby no lactose is left in the fresh cheese after fermentation to the correct fresh cheese pH level of 5.2.
• the highly viscous retentate is continuously led out of the ultrafiltration apparatus by means of a positive pump and is pumped through a system of scraped surface heat exchangers for a heat treatment and is cooled to fermentation and renneting temperature.
• the heat treatment the retentate is heated to 69°C ( ⁇ H C C) for about 20 seconds, whereupon it is immediately cooled to 31°C.
• the temperature/time relationship is essential to the further processing of the retentate.
• the necessary additives, starter culture and rennet as well as optionally nitrate, calcium chloride, colour, salt and ripening enzymes are in—line dosed and the additives are mixed into the retentate.
• the material is led to a specially contructed mould filling system in which the material is continuously filled into moulds, e.g. made of plastic material.
• the moulds After renneting, the moulds are automatically transported to a mould stacking system in which the cheeses are stored for some hours at room temperature in order to cure before demoulding.
• the demoulding procedure takes place automa- tically and the cheeses are also automatically placed on a shelf system where they are kept until they have complet ⁇ ed acidification.
• the fermentation process taking place in the mould and on the shelf system, takes less than 15 hours in spite of the high buffer capacity in the precheese, whereupon the pH is 5.2.
• a combination of mesophilic DVS starters (20g B-ll and 20 g R-603 per 100 kg retentate, available from Chr. Hansens Laboratorium) is used to obtain the desired fermentation process.
• a standard rennet (rennetability 1:15 , 000 , 20 ml per 100 kg retentate, Chr. Hansens Laboratorium) is added.
• the brining and ripening conditions are the same as in conven ⁇ tional cheesemaking.
• Brining may start even earlier than 15 hours after ren— neting, because the cheese may be placed in the brine already when the pH is 5.6—5.8. This will not affect the quality of the cheese.
• the ripening conditions as regards tempearature , humidity and surface tratment correspond to those of conventional treatment.
• the yellow, cast cheese produced by the process according to the invention has an even milder taste, as the yellow cast cheese has been produced on the basis of a 7.5-8 times concentrated ultrafiltration reten ⁇ tate.
• the consistency of the yellow, cast cheese is also found to be acceptable. The consistency is smooth and at the same time sufficiently firm for the cheese to be sliced easily .
• the present example describes the production of a cheese of the type 45+, i.e. having approx. 45% fat in relation to the dry matter content.
• the raw milk is standardized to a fat content (fat %)of 1.0 times the protein % and pasteurized using a plate heat exchanger by heating to 72 ⁇ C for 15 seconds, whereupon It Is cooled to 6°C on a plate heat exchanger.
• the milk is then reheated to 50°C on a plate heat exchanger and subjected to ultrafIltration in an ultrafiltration system (DDS plate and frame system, module 38 and module 37, available from Dow Danmark A/S , Nakskov, Denmark) with diafIltration to obtain a retentate having a dry matter content of 48—49% by weight and a lactose content of 1.1% by weight.
• DDS plate and frame system module 38 and module 37, available from Dow Danmark A/S , Nakskov, Denmark
• Rennet standard rennet, rennetability 1:15,000, 20 ml per 100 kg retentate
• starter culture (20 g DVS B-ll and 20 g DVS R-603 per 100 kg. retentate) and KN0 3 (10 g per 100 kg retentate)
• KN0 3 10 g per 100 kg retentate
• the present example illustrates the production of a cheese of the type 20+.
• the milk is then reheated to 50°C on a plate heat exchanger and subjected to ultrafiltration in a DDS ultrafiltration apparatus of the plate and frame type with diafiltration to obtain a retentate having a dry matter content of 40—41% by weight and a lactose content of 1.6% by weight.
• the retentate is heated continuously to 65 C C for 30 seconds and then cooled to approx. 31°C.
• Rennet, starter culture and KN0 3 (as in Example 2) are admixed in form of an aqueous suspension in volume of 1% of the volume of the retentate. Mixing, casting and after- treatment are carrried out as described in Example 2. After ripening, the cheese has a satisfactory consistency and taste .
• the present example illustrates the production of a cheese of the type 30+.
• the raw milk is standardized to a fat content whereby fat % - protein % times 0.46 and is pasteurized using a plate heat exchanger by heating to 72 C C for 15 seconds, whereupon it is cooled to 50°C on a plate heat exchanger and sub ⁇ jected to ultrafiltration in a DDS ultrafiltration ap- paratus of the plate and frame type with diafiltration to obtain a retentate having a dry matter content of 42-43% by weight and a lactose content of 1.4% by weight.
• the retentate is heated continuously to 65°C for 30 seconds and then cooled to approx. 31°C.
• Rennet, starter culture and KNO a (as in Example 2) are admixed in form of a suspen ⁇ sion in a volume of 1% of the volume of the retentate.
• the further treatment is carried out as described in Example 2.
• a good cheese both as regards consistency and taste is obtained.
• the present example illustrates the production of a cheese of the type 50+.
• the raw milk is standardized to a fat content of fat % - protein % times 1.25 and Is pasteurized using a plate heat exchanger by heating to 72°C for 15 seconds, whereupon it is cooled to 6 c C.
• the milk is reheated to 50°C on a plate heat exchanger and subjected to ultrafIltration in a DDS ultrafIltration apparatus of the plate and frame type with diafiltration to obtain a retentate having a dry matter content of 50-51% by weight and a lactose content of 1.0% by weight.
• the retentate is heated continuously to 69°C for 20 seconds and then cooled to approx. 31°C.
• Rennet, starter culture and KN0 3 (as in Example 2) are admixed in form of a suspension in a volume of 1% of the volume of the retentate.
• the further treatment is carried out as described in Example 2.
• An attractive full—cream cheese both as regards consistency and taste Is obtained.

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• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Polymers & Plastics (AREA)
• Dairy Products (AREA)

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• 1991
  • 1991-05-21 DK DK095491A patent/DK168354B1/da not_active IP Right Cessation
• 1992
  • 1992-05-19 NZ NZ242803A patent/NZ242803A/en not_active IP Right Cessation
  • 1992-05-20 AU AU18839/92A patent/AU661848B2/en not_active Ceased
  • 1992-05-20 WO PCT/DK1992/000163 patent/WO1992020216A1/en active IP Right Grant
  • 1992-05-20 US US08/142,375 patent/US5447731A/en not_active Expired - Lifetime
  • 1992-05-20 JP JP4510390A patent/JPH06507546A/ja active Pending
  • 1992-05-20 ES ES92911077T patent/ES2106870T3/es not_active Expired - Lifetime
  • 1992-05-20 DE DE69220947T patent/DE69220947T2/de not_active Expired - Fee Related
  • 1992-05-20 EP EP92911077A patent/EP0591247B1/de not_active Expired - Lifetime
  • 1992-07-01 IE IE921617A patent/IE80497B1/en not_active IP Right Cessation

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